Self-restrained ductile iron fitting

A combination sealing and restraint system for insertion within an annular groove provided within a mouth region located adjacent an end opening of an as-cast ductile iron fitting capable of both sealing and restraining the ductile iron fitting to a mating male pipe having an interior surface and an exterior surface, the sealing and restraint system comprising:

• an annular gasket body made of a resilient elastomeric material, the annular gasket body having an inner circumferential region and an outer circumferential region, the annular gasket body being installed within the annular groove provided in the mouth region of the as-cast fitting so that the outer circumferential region forms a seal with the fitting mouth region and the inner circumferential region forms a sealing surface for a mating male pipe section;
• a plurality of generally planar metallic gripping segments extending perpendicularly outward from the annular gasket body at a predetermined spacing around the circumference of the annular gasket body;
• wherein the gripping segments are comprised of an inner planar surface and an outer planar surface separated by a thickness, and wherein the inner planar surface has at least one row of gripping teeth capable of engaging selected points on the exterior surface of the mating male pipe and apply a gripping force to the exterior surface;
• wherein the sealing surface of the annular gasket body extends further radially inward in a direction of a centerline of the mouth opening of the fitting than do the gripping teeth on the inner planar surfaces of the gripping segments;
• and
• wherein the outer planar surfaces of the gripping segments are at least partly covered with elastomeric material from the gasket body, so that the gripping force exerted on the exterior surface of the mating male pipe can be controlled by varying the amount of elastomer and by varying the durometer of the elastomer.